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IEEE 802.11g-2003 or 802.11g is an amendment to the IEEE 802.11 specification that operates in the 2.4 GHz microwave band. The standard has extended link rate to up to 54 Mbit/s using the same 20 MHz bandwidth as 802.11b uses to achieve 11 Mbit/s.
802.11-1997 was the first wireless networking standard in the family, but 802.11b was the first widely accepted one, followed by 802.11a, 802.11g, 802.11n, 802.11ac, and 802.11ax. Other standards in the family (c–f, h, j) are service amendments that are used to extend the current scope of the existing standard, which amendments may also include corrections to a previous specification.
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Wireless LAN (WLAN) channels are frequently accessed using IEEE 802.11 protocols. The 802.11 standard provides several radio frequency bands for use in Wi-Fi communications, each divided into a multitude of channels numbered at 5 MHz spacing (except in the 45/60 GHz band, where they are 0.54/1.08/2.16 GHz apart) between the centre ...
#F 0 (mhz)Dsss(frequency Range (mhz))Dsss(channel 22 Mhz)1424842473–2495141324722461–2483111224672456–2478111124622451–247311Wi-Fi (/ ˈwaɪfaɪ /) [1][a] is a family of wireless network protocols based on the IEEE 802.11 family of standards, which are commonly used for local area networking of devices and Internet access, allowing nearby digital devices to exchange data by radio waves. These are the most widely used computer networks, used globally in ...
- Introduction
- Applications
- Large-Scale Deployments
- Increasing Range in Other Ways
- Obstacles to Long-Range Wi-Fi
- Notable Links
- See Also
- External Links
Since the development of the IEEE 802.11 radio standard (marketed under the Wi-Fi brand name), the technology has become markedly less expensive and achieved higher bit rates. Long-range Wi-Fi especially in the 2.4 GHz band (as the shorter-range higher-bit-rate 5.8 GHz bands become popular alternatives to wired LAN connections) have proliferated wi...
Business
1. Provide coverage to a large office or business complex or campus. 2. Establish point-to-point link between large skyscrapers or other office buildings or airports. 3. Bring Internet to remote construction sites or research labs. 4. Simplify networking technologies by coalescing around a small number of Internet related widely used technologies, limiting or eliminating legacy technologies such as shortwave radio so these can be dedicated to uses where they actually are needed. 5. Bring Inte...
Nonprofit and Government
1. Connect widespread physical guard posts, e.g. for foresters, that guard a physical area, without any new wiring 2. In tourist regions, fill in cell dead zones with Wi-Fi coverage, and ensure connectivity for local tourist trade operators 3. Reduce costs of dedicated network infrastructure and improve security by applying modern encryption and authentication.
Military
1. Connect critical opinion leaders, infrastructure such as schools and police stations, in a network local authorities can maintain 2. Build resilient infrastructure with cheaper equipment that an impoverished war-torn region can afford, i.e. using commercial grade, rather than military-class network technology, which may then be left with the developed-world military 3. Reduce costs and simplify/protect supply chains by using cheaper simpler equipment that draws less fuel and battery power;...
The Technology and Infrastructure for Emerging Regions (TIER) project at University of California at Berkeley in collaboration with Intel, uses a modified Wi-Fi setup to create long-distance point-to-point links for several of its projects in the developing world. This technique, dubbed Wi-Fi over Long Distance (WiLD), is used to connect the Aravin...
Specialized Wi-Fi channels
In most standard Wi-Fi routers, the three standards, a, b and g, are enough. But in long-range Wi-Fi, special technologies are used to get the most out of a Wi-Fi connection. The 802.11-2007 standard adds 10 MHz and 5 MHz OFDM modes to the 802.11a standard, and extend the time of cyclic prefix protectionfrom 0.8 μs to 3.2 μs, quadrupling the multipath distortion protection. Some commonly available 802.11a/g chipsets support the OFDM 'half-clocking' and 'quarter-clocking' that is in the 2007 s...
Power increase or receiver sensitivity boosting
Another way of adding range uses a power amplifier. Commonly known as "range extender amplifiers" these small devices usually supply around 1⁄2watt of power to the antenna. Such amplifiers may give more than five times the range to an existing network. Every 3 dB gain doubles the effective output power. An antenna receiving 1 watt of power, and 6 dB gain would have an effective power of 4 watts.
Higher gain antennas and adapter placement
Specially shaped directional antennas can increase the range of a Wi-Fi transmission without a drastic increase in transmission power. High gain antenna may be of many designs, but all allow transmitting a narrow signal beam over greater distance than a non-directional antenna, often nulling out nearby interference sources. Such "WokFi" techniques typically yield gains more than 10 dB over the bare system;enough for line of sight (LOS) ranges of several kilometers (miles) and improvements in...
Methods that increase the range of a Wi-Fi connection may also make it fragile and volatile, due to various factors including:
Italy
The longest unamplified Wi-Fi link is a 304 km link achieved by CISAR (Italian Center for Radio Activities).New world record for long-range wireless broadband. 1. link first established on 2016-05-07 and 2016-05-08 2. it appears to be permanent from Monte Amiata (Tuscany) to Monte Limbara (Sardinia) 3. frequency: 5765 MHz 4. IEEE 802.11a (Wi-Fi), bandwidth 50 MHz 5. data rates: of up to 356.33 Mbit/s 6. Radio: Ubiquiti NetworksAF-5X radios 7. Wireless routers: UbiquitiairFiber 8. Length:304 k...
Venezuela
Another notable unamplified Wi-Fi link is a 279 km (173 mi) link achieved by the Latin American Networking School Foundation. 1. Pico del Águila– El Baúl Link. 2. frequency: 2412 MHz 3. link established in 2006 4. IEEE 802.11 (Wi-Fi), channel 1, bandwidth 22 MHz 5. Wireless routers: Linksys WRT54G, OpenWrt firmware at el Águila and DD-WRTfirmware at El Baúl. 6. Length:279 km (173 mi). 7. Parabolic dish antennas were used at both ends, recycled from satellite service. 8. At El Aguila site an a...
Peru
Loreto, in the jungle region of Peru, is the location of the longest Wi-Fi-based multihop network in the world. This network has been implemented by the Rural Telecommunications Research Group of the Pontificia Universidad Católica del Perú (GTR PUCP). The Wi-Fi chain goes through many small villages and takes seventeen hops to cover the whole distance. It begins in Cabo Pantoja's Health Post and finishes at downtown Iquitos. Its length is about 445 km (277 mi). The intervention zone was esta...
Wi-Fi 6, or IEEE 802.11ax, is an IEEE standard from the Wi-Fi Alliance, for wireless networks (WLANs). It operates in the 2.4 GHz and 5 GHz bands, [9] with an extended version, Wi-Fi 6E, that adds the 6 GHz band. [10] It is an upgrade from Wi-Fi 5 (802.11ac), with improvements for better performance in crowded places.
Wireless technologies can be evaluated by a variety of different metrics of which some are described in this entry. Standards can be grouped as follows in increasing range order: Personal area network (PAN) systems are intended for short range communication between devices typically controlled by a single person.
